Dental instrument

ABSTRACT

THE PRESENT INVENTION RELATES TO A DENTAL INSTRUMENT FOR MIXING AND DISCHARGING AMALGAM TO BE FILLED INTO A CAVITY IN A TOOTH AND THE OBJECT OF THE INVENTION IS TO PROVIDE SUCH AN INSTRUMENT THAT CAN BE OPERATED BY THE DENTIST HIMSELF WITHOUT THE NEED OF ANY ASSISTANT. THE INSTRUMENT ACCORDING TO THE INVENTION COMPRISES TO THIS END A SCREW DRIVEN BY A MOTOR AND ROTATABLY HOUSED IN A SCREW HOUSING, THE LATTER PROVIDED WITH A DEVICE FOR INTRODUCING A SILVER ALLOY IN THE SHAPE OF A POWDER, THAT MAY BE COMPRESSED, AND MERCURY AT ONE OF ITS ENDS AND HAVING OPENINGS TO ALLOW A PRESSING OUT OF MERCURY IN EXCESS AT ITS OPPOSITE END AND IN A KNOWN, TUBE-SHAPED CHANNEL IN COMMUNICATION WITH THE DISCHARGE END OF THE SCREW HOUSING AND A MEANS DISPLACEABLE IN SAID CHANNEL FOR PRESSING OUT, IN PORTIONS, AMALGAM AT THE OPENING OF THE CHANNEL INTO THE TOOTH TO BE FILLED, SAID DISPLACEABLE MEANS ADAPTED TO CLOSE, MOMENTARILY, THE DISCHARGE END OF THE SCREW HOUSING.

Jan. 5, 1971 G. I; s. OSBECK 3,552,023

DENTAL INSTRUMENT Fild Jan. 15, 1969 2 Sheets-Sheet 2 Fig.2 Fig.3

INVENTOR. OS BECK ATTORNEYS 3,552,023 DENTAL INSTRUMENT Gunnar Ingemar Sigvard Osbeck, 35 Vasagatan, S411 37 Goteborg, Sweden Filed Jan. 16, 1969, Ser. No. 791,696 Claims priority, application Sweden, Jan. 17, 1968, 599/68 U.S. Cl. A61c /04 US. Cl. 32-60 4 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to a dental instrument for mixing and discharging amalgam to be filled into a cavity in a tooth and the object of the invention is to provide such an instrument that can be operated by the dentist himself without the need of any assistant. The instrument according to the invention comprises to this end a screw driven by a motor and rotatably housed in a screw housing, the latter provided with a device for introducing a silver alloy in the shape of a powder, that may be compressed, and mercury at one of its ends and having openings to allow a pressing out of mercury in excess at its opposite end and in a known, tube-shaped channel in communication with the discharge end of the screw housing and a means displaceable in said channel for pressing out, in portions, amalgam at the opening of the channel into the tooth to be filled, said displaceable means adapted to close, momentarily, the discharge end of the screw housing.

DISCLOSURE OF THE INVENTION When a dentist has drilled a cavity in a tooth and is to perform a filling with amalgam, he as known calls his nurse who prepares the required quantity of amalgam on a small plate. The mixing of the silver alloy powder and the mercury is mostly carried out manually but may also be performed by means of a vibrating instrument. The nurse kneads the treatment material and by means of her fingers she presses out mercury in excess and delivers said material in a filling instrument in small quantities of prepared amalgam to the dentist who successively fills the cavity in the tooth.

The present invention relates to a dental instrument which to a large extent facilitates the operation described here above and the nurse will no longer be necessary for this job. The main feature of the invention is that the instrument comprises a screw which is driven by a motor and which is journalled in the screw housing provided with a device for the insertion of a possibly compressed powder of a silver alloy and mercury at one end and is provided with openings for expelling mercury in excess at its opposite end and a tube shaped channel in communication with the discharge end of the screw housing and a means displaceable therein for an expelling of amalgam in portions at the mouth of the channel into the tooth to be filled. The displaceable means is adapted to close, momentarily, the discharge end of the screw housing. The channel mouth proper may be used as a stuffing or compressing means for filling the cavity. Due to the rotating screw there is obtained an effective mixing of the alloy powder and the mercury.

The filling and stufiing work is facilitated when-- according to one embodiment of the invention-the instrument is provided with a vibrator. By means of a vibration of the treatment material the latter may be made very fluent. The material may then be easily inserted into coners of the cavity in the tooth to be filled. At a compression of the material in the interior of the screw housing by means of a rotation of the screw, the excess of mercury is expelled such that at the continued filling of "ntted States Patent 0 3,552,023 Patented Jan. 5, 1971 the tooth the material in a desired way is made more firm.

It is suitable if the stuffing or compressing tool proper, i.e. the channel with the means displaceable therein, is removably arranged in the screw housing. In such a case this tool which advantageously is made of synthetic resin, may be dispensed with at the completion of work on a patient. Any sterilization of the instrument, the main portion of which never is brought into contact with the patient, thus will never be necessary.

The invention will now be elucidated with reference to the accompanying drawings. In the drawings:

FIG. 1 shows a longitudinal section through a dental instrument according to the invention,

FIG. 2 shows a cross section on the line IIII in FIG. 1,

FIG. 3 shows an end elevation of the instrument shown in FIG. 1 after the removal of the tube shaped means from the screw housing,

FIG. 4 is a side elevation of the compression tool, and

FIG. 5 shows a vertical section through a tooth and a side elevation of a compression tool according to the invention at operation.

The instrument shown in the drawings comprises an elongated screw housing 1, a screw 2 being carried for rotation therein. The screw 2 is rotated by means of an electric motor 4, driven by means of electric batteries 3, via a gearing device 5 and a sliding coupling 6. When the instrument is not in use, the batteries 3 may be charged via a rectifier 7 connected to the electric system, the instrument being coupled to the rectifier 7 via a pair of coupling pins 8. The motor is started by means of a push button switch 9.

The screw 2 tapers conically from its driven end where the screw housing 1 is provided with a feeding funnel 10 for alloy metal powder and mercury in the direction toward its discharge end 11. The bore 12 in which the screw 2 is housed, is provided with longitudinal grooves 13 which prevent the treatment material, i.e. the amalgam, from rotating together with the screw. Close to the discharge end 11 the screw housing is provided with sidewards directed openings 14 which open in a container 15 removable from the screw housing and intended to collect excess mercury expelled from the treatment material.

The electric equipment also comprises a high frequency vibrator 16 connectable to the batteries 3 via the switch 9.

The compression tool 17 proper comprises a tube shaped channel 18 enclosing an acute angle with the longitudinal axis of the screw 2, the bore 12 debouching at the discharge end 11 in said channel 18. Axially displaceable in the channel 18 is a piston 19 which in its rear position (shown in FIG. 1) frees the discharge opening 11 but at a displacement into the channel 18 by means of an operation handle 20 against the action of a helical spring 21 closes the discharge opening 11 and presses material inserted into the channel 18, through the channel mouth 22. The compression tool 17 is by means of a bayonet catch 23 removably attached to the discharge end of the screw housing 1.

The instrument is preferably provided with cassettes which are releasably attachable and which contain on the one hand a number of tablets of powdery silver alloy (silver-tin-copper) each of a volume of e.g. cm. and on the other hand mercury in suitable measured quantities and with means for introducing the desired number of tablets and the required quantity of mercury into the bore 12 of the housing 1.

After the introduction of the tablets and the mercury into the bore 12, the motor 4 is started and then the screw 2 starts to rotate. The silver alloy is then mixed with the mercury and the mixing operation is facilitated if the screw housing and the mixture material are vibrated by means of the vibrator 16. During the mixing operation, the piston 19 is situated in front of the discharge opening 11. The material in the bore 12 is compressed in the discharge end 11 and excessive mercury is pressed through the openings 14 into the container 15. The piston 19 is then moved backwards to the outer position shown in FIG. 1 and the treated material is fed by the screw 2 into the channel 18 towards the mouth 22. The operation handle 20 which may be replaced by a one or two-armed lever mounted on the screw housing 1 or on the compression tool 17 proper, is used for pressing prepared amalgam out of the discharge end 24 of the compression tool 17 and into the cavity 25 of the tooth 26 (FIG. 5) to be filled. The end 24 may then be used as compression means for pressing the amalgam 27 into the cavity 25. This compression work is facilitated and improved due to the vibrations produced by means of the vibrator 16.

It is also possible to operate with the compression tool 17 separately, i.e, coupled from the screw housing 1. It

is then from the channel 18, filled with amalgam 27, small quantities of amalgam pressed into the cavity and the end 24 may then be used as a compression and packing tool. However, if it is desired to introduce the amalgam into the undercut part of the cavity, one may in a conventional way use the stutter comprised in the dental equipment.

The screw housing 1 and the compression tool 17 may be manufactured integrally. The motor 4 may be connectable directly or via a transformator and a flexible cable to the electric net. The same is true for the vibrator 16. The piston 19 may take the form of a screw piston of the end of the piston extending through the compression tool 17 may be threaded such that it is rendered possible to press the treatment material out of the mouth 22 by means of screw force.

What I claim is:

1. A dental instrument for filling amalgam into tooth cavities comprising a screw, conically tapered from its driven end, driven by a motor and rotatably housed in a housing having longitudinal grooves in the internal surface of said housing and paralleling said screw from the larger diameter, driven end to the other, smaller diameter end thereof, said housing having an opening near the driven end of said screw for introduction of powdered metal alloy and mercury and openings in said housing toward the other end of said housing adapted to allow exit of pressed out, excess mercury, tube-shaped means in communication with the discharge end of said housing, and means displaceable in said tube-shaped means for pressing out of said tube-shaped means and into a tooth cavity, amalgam coming from the exit of said housing, also said displaceable means being adapted to close, at least momentarily, the discharge end of said screw housmg.

2. An instrument as claimed in claim 1, wherein the improvement comprises an expelling means in the channel in the shape of a piston which is displaceable by means of an operation handle, said piston adapted to close, in a certain displacement position in the channel, the discharge end of the screw housing.

3. An instrument as claimed in claim 1, wherein the improvement comprises an electrically driven vibrator at the screw housing adapted to vibrate the amalgam about the screw.

4. An instrument as claimed in claim 1, wherein the improvement comprises providing the screw housing outside the openings at the discharge opening with a container for collecting expelled mercury.

References Cited UNITED STATES PATENTS 3,322,307 5/1967 Fraser 326OX FOREIGN PATENTS 483,465 3/1927 Germany 32-60 ROBERT PESHOCK, Primary Examiner 

